The present invention relates to a sealing system between three flat components. In a more specific aspect, the invention is concerned with surveying instrument casings made up of plastic parts provided with edge portions of distinctive shapes that permit such portions to be snapped together to form a completed casing that will not leak and that will protect the instrument from deterioration stemming from the influence of moisture.
It has been proposed to form sealing joints from two oblong sealing elements interlocking along the edges of the components to be joined. One of the sealing elements is shaped as a receiving element and the other is shaped as an inserting element adapted to be inserted into the receiving elements, as shown in West German Patent Application DE-A-2904636 (Modern Precision Engineers). Such joints fail to give a tight seal when three components must be joined together because the change-over from receiving element to inserting element on the same component will produce leaks.
One of the objects of the present invention is to provide a sealing system between interlocking sealing elements that will give a tight seal even when three joints, each between two components, intersect in one common point.